This invention relates generally to web-based distribution of content, such as advertising, and more specifically to targeting advertising to a specific set of users without sharing the identities of the users to whom the advertising is targeted.
An advertiser may want to display online advertisements to users who are likely interested in an advertised product. Advertisers, such as online merchants, typically collect data about their users and determine advertisements that are suited to a particular user based on that collected data. The advertisers may then send the advertisement, along with some form of metadata associating that advertisement with the user, to an ad publisher. This poses a number of challenges.
Traditionally, advertisers use “cookies” stored on a user's device to indicate to an ad publisher to serve a particular ad to the user. This is problematic in the modern age, as one user may have multiple devices (such as a laptop computer, a desktop computer, or a mobile phone), and multiple users may share a single device. Since there is often not a one-to-one relationship between users and devices, a cookie stored on a device is an inaccurate way to target advertising to a particular user. For example, if advertisers gather information on a user while the user is using one device, and then the user switches to a different device, this information could not be used to inform ad publishers when the user is using the second device.
Instead of using cookies, an advertiser could directly send the information to the ad publisher indicating the identities of the users who are to receive a particular ad. This would allow for the advertiser and the ad publisher to target the user no matter which device they are using. However, the user may have no previous relationship with the ad publisher or otherwise want to create a relationship with the ad publisher. By directly sending the user's information, the ad source risks exposing the user's personally identifiable information (PII), as well as other information, to the ad publisher, as well the broader public. This type of exposure threatens the user's privacy. For example, an ad publisher may not already have the PII of a user, and if the advertiser identifies the user to the ad publisher (e.g., by email address) this will result in the possibly unwanted sharing of the user's PII with the ad publisher. Due to laws governing privacy, as well as user-distrust of companies that risk the privacy of their information, advertisers would be remiss to exposes their users' PII.
Advertisers have not yet been able to securely communicate targeted advertisements to users, regardless of their device, without exposing the users' information to the ad publishers who do not otherwise have the information.